Question

What is the ratio of the frequencies of the notes emitted (1) by an open pipe and (ii) by a closed pipe of the same length.

Answer 1

For a closed pipe in case of fundamental note l = λ/4 or λ = 4l, therefore n = v/λ = v/4l

For an open pipe l = λ/2. Therefore n′ = v /2l

Comparing (i) and (ii) we find that n′ = 2n.